Prions-New infectious agents.

A report in the Spring 2000 Mayo Alumni, "A scientific odyssey--of sheep, 'mad' cows and a tiny protein," describes the fascinating work of Stanley B. Prusiner, MD, Professor of Neurology and Biochemistry at the University of California School of Medicine, San Francisco, and Professor of Virology in Residence at the University of California, Berkeley.

Dr. Prusiner won the 1997 Nobel Prize in Physiology and Medicine for his work to define and introduce "prions." He described his "scientific odyssey" to the discovery of these infectious particles at the annual Occidental Petroleum Nobel Laureate Lecture at the Mayo Clinic. The article considered key to his winning the Nobel Prize was "Novel proteinaceous infectious particles cause scrapie" (Science, April 1982, Vol. 216, pp. 136-44).

The prion is a proteinaceous infectious particle that Dr. Prusiner added to the known list of infectious agents, which includes bacteria, viruses, fungi, and parasites. Dr. Prusiner was stimulated in his investigations when, as a resident in Neurology in 1972, he cared for a 62-year-old patient who died of Creutzfeldt-Jakob disease. The disease was then thought to be caused by a slow virus. "At the time, I was intrigued by a disease process that could kill a patient in just two months by destroying her brain while her body remained unaffected by the process," recalls Dr. Prusiner.

After years of intensive research, much has been learned about prions. They are unique in that they apparently contain no nucleic acid, such as DNA or RNA, as do other infectious agents. Prions are now thought to be the possible causes of degenerative brain diseases, such as Alzheimer's disease, multiple sclerosis (MS), Parkinson's disease, and amyotrophic lateral sclerosis (ALS).

The outbreak in Great Britain in the 1980s of mad cow disease (bovine spongiform encephalopathy, or BSE), a prion-caused disease, was traced to a cattle food supply that had been supplemented with remains of scrapie-infected sheep. Understanding the diseases caused by prions has been made difficult by the low rate of infection and an unusually long incubation time. Clues in scientific research are often sparse. Many years ago I read a report suggesting that MS might have been caused by a pet dog brought to the Faroe Islands by a soldier during World War II some 20 years earlier. I learned from my National Geographic Atlas of the World that the isolated Faroe Islands lie in the North Atlantic Ocean between England and Iceland. The possible cause of MS by a prion fits the profile of a long incubation, an animal vector, and complete isolation from other factors.

The implications of Dr. Prusiner's important work for otolaryngology are great. Many unexplained cases of progressive hearing loss, vertigo, ataxia, tinnitus, idiopathic hemifacial spasm, and other progressive nose and throat diseases might eventually be linked to prions. This new theoretical basis for the treatment of diseases offers great promise for our patients.

JACK L. PULEC

Editor-in-Chief

EAR, NOSE & THROAT JOURNAL